Tidal 55 HOB

Performance & sizing

Core numbers for matching this unit to your tank and electrical plan.

Power

6 W

Flow rate

1000 L/h

Dimensions

20.5x15.5x21.4

Tank fit

≤ 200 L

Running cost (electric)

At continuous full load (6 W), approximate draw is ~4.3 kWh per month (24/7). Actual use depends on dimming, duty cycles, and thermostat control.

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Specifications

Values as listed by each source when checked on 2026-09-15. Listings change.

Description

The Seachem Tidal 55 is a hang-on-back filter rated by Seachem for aquariums up to 200 L (55 US gallons), moving 1000 L/H (250 US GPH) on a 6 W pump. What separates it from most HOBs is that it takes no cartridges: the basket is an open 1.2 L chamber you fill with media of your choice, and it ships with Seachem's own Matrix bio-media and a foam pad to start. The flow path is bottom-to-top. The pump pushes water up through the underside of the basket and out the top, which Seachem contrasts with the back-to-front HOBs where water can slip around the media rather than through it. Two dials control what the filter draws: one sets pump output, the other balances the sub-surface intake against the surface skimmer. That skimmer is the reason this filter gets recommended for planted tanks - it pulls the oily protein film off the surface, and the ventilation slots and aeration grooves in the return keep gas exchange up. There is a maintenance alert worth knowing about. When the media clogs, water is redirected around it and out a side outlet, and that bypass flow pushes a blue indicator up on the lid. A raised indicator means the filter is running but no longer filtering properly. The basket lifts out and clips into the lid for a drip-free carry to the sink; the pump is self-priming and the impeller self-cleaning and corrosion-resistant, so it runs in fresh or salt water. Plan the space before buying. The unit is 20.5 x 15.5 x 21.4 cm and Seachem specifies 7.5 cm of wall clearance behind the tank plus 2.6 cm of trim clearance - a cabinet against a wall often will not take it. A telescoping intake lets you draw from any depth without stopping the filter, an optional clip hangs a heater on the side, and the warranty is three years, extendable to five on registration.

Source

• seachem.com — https://www.seachem.com/tidal-55.php

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